[Devel] Re: Distiller produced PFA problems

[Tom Kacvinsky]

Which brings me to the other point...  FreeType currently assumes
a unit per em of 1000. This font uses a unit per em of 2048.  I guess
I need to come up with a hueristic to get the right unit per em...

Tom

On Tue, 23 Jan 2001, Tom Kacvinsky wrote:

> Ugh...  That wasn't it.  I had changed the FontMatrix to be a 1000 units per 
> em
> scale instead of 2048 units per em scale (the reason why I chose the latter
> number is because the font was clearly autoconverted from TT to Type 1 by some
> Windows print driver, and the resulting Type 1 font was distilled into a PDF
> file).
>
> Any way, once I changed the font matrix back, things looked fine...
>
> It might help me a *lot* if I saw one of the PDF files you guys are trying to
> rasterize.  There is more font info in a PDF file than just the FontFile,
> FontFile2, or FontFile3 streams...
>
> Tom
>
> On Tue, 23 Jan 2001, Tom Kacvinsky wrote:
>
> > I suspect this might have to do with the fact that the FontBBox in the font 
> > you
> > sent me is {0 0 0 0}.  Does this over magnification happen if the FontBBox 
> > is
> > non-zero (by zero bbox, I mean all entries are zero.  a non-zero bbox then 
> > means
> > that not all entries are zero.  this is the mathematician in me speaking. :)
> >
> > Tom
> >
> > On Tue, 23 Jan 2001, Blinn, Eric W wrote:
> >
> > >
> > > Hi Tom,
> > >
> > > Thanks.  With your patch we are almost there with Distiller produced PFAs,
> > > but there is still one problem.  We now have glyphs and metrics to work 
> > > with
> > > and they look good, but the glyphs themselves need to be scaled down by 
> > > 50%.
> > >
> > > I have a local fix... okay hack really, where I'm keying off some of the
> > > missing FontInfo data to detect that we are dealing with a Distiller
> > > produced PFA and then scaling the font matrix xx and yy values back by 
> > > half.
> > > Not a fix I'll want to stick with mind you, just "proof of concept" in the
> > > course of troubleshooting.  I'll leave it to you and the other FreeType
> > > gurus to determine how and where to handle this in the library.
> > >
> > > Thanks,
> > > Eric
> > >
> > >
> > > > -----Original Message-----
> > > > From: Tom Kacvinsky [mailto:address@hidden
> > > > Sent: Monday, January 22, 2001 11:34 PM
> > > > To: address@hidden
> > > > Subject: [Devel] Re: Distiller produced PFA problems
> > > >
> > > >
> > > > Well, here is the patch.  I have yet to add dummy FontInfo support (I
> > > > am still thinking about how best to approach it).  I send this patch
> > > > along for review before I commit it.  The thing to note is that the
> > > > test I removed prevented one from parsing the dictionaries if the
> > > > FontInfo keyword was never seen.  Now that test is gone, and things
> > > > work fine.  I tested with both MM and regular Type 1 fonts, and had no
> > > > problems.
> > > >
> > > > Oh yeah, I rechecked my Type 1 notes: it is OtherSubrs that can be
> > > > missing from the font, and ATM and its ilk is *supposed* to provide
> > > > defaults.  If any given char string uses a subroutine, all subroutines
> > > > must be present (whereas I had previously thought that subrs 0 - 3
> > > > could be missing).  What I will do is add code that will return an
> > > > error if the font uses subroutines and the Subrs array is missing.
> > > > This, I think, is supposed to go into t1decode.c (part of the psaux
> > > > module).
> > > >
> > > > Tom
> > > >
> > > > On Mon, 22 Jan 2001, Tom Kacvinsky wrote:
> > > >
> > > > > Hi,
> > > > >
> > > > > I will get the patch out tonight.  I know what to change, I
> > > > just need to make
> > > > > sure that there aren't any ill side affects.
> > > > >
> > > > > Tom
> > > > >
> > > > > On Mon, 22 Jan 2001, Blinn, Eric W wrote:
> > > > >
> > > > > >
> > > > > > Tom Kacvinsky wrote:
> > > > > > >
> > > > > > > I found the problem, finally.  There is bug in FreeType that
> > > > > > > reports there is no CharStrings dictionary when there is one.
> > > > > > > Adding a FontInfo dictionary causes the false report to go
> > > > > > > away.  I'll see what I can come up with.
> > > > > >
> > > > > > Thanks for all the effort Tom.  Since you've found the problem
> > > > > > this information probably has little value, but you had asked
> > > > > > in another message about whether I had added a dummy FontInfo
> > > > > > dictionary when testing your fix on my platforms.  I had not,
> > > > > > but the analysis you gave pretty well explains how the dummy
> > > > > > FontInfo data was masking the CharStrings dictionary bug at
> > > > > > your end.
> > > > > >
> > > > > >
> > > > > > > Eric, I hope this isn't causing you too much stress, what
> > > > > > > with the 11th hour show stopper you were referring to...
> > > > > >
> > > > > > Well, maybe only a couple days of stress!  :-)
> > > > > > It looked like it could hold up our release, but since then
> > > > > > we have done a risk analysis.  With the data we're handling,
> > > > > > we don't think it will be a problem in the immediate future
> > > > > > but it could be (likely will be) down the road.  Now that
> > > > > > you have a handle on the problem, I'll just roll whatever
> > > > > > fix you settle on into our next release (or perhaps even this
> > > > > > one if circumstances permit).
> > > > > >
> > > > >
> > > > >
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